Effect of geometry and anisotropy of a Hele-Shaw cell on viscous fingering of polymer solutions

Viscous fingering patterns of hydroxypropyl methyl cellulose (HPMC) solutions were investigated by forcing air in radial and linear geometry Hele-Shaw cells with radial and linear geometry as functions of HPMC concentration and applied pressure. The resulting patterns depended on the HPMC concentration and the cell geometry and anisotropy. The characteristic quantities of pattern growth, such as the finger tip velocity and the finger width, were evaluated. The tip velocity in the anisotropic linear cell was almost the same as that in the radial one, moreover, the finger width was well correlated with the pattern morphological changes.